JP4764672B2 - Method for measuring powder material - Google Patents

Description

  The present invention relates to an improvement of a one-batch weighing method in which a granular material is weighed by a certain amount by supplying the granular material from a hopper to a measuring device.

  Conventionally, powder material stored in the hopper is dropped from the material discharge port by opening the flap damper or slide shutter provided at the bottom of the hopper, received by a measuring instrument equipped with a load cell, and then weighed there. The method is known.

In this type of measuring method, even if the opening degree of the material discharge port is kept constant, the supply amount increases exponentially because the granular material is affected by the gravitational acceleration.
For this reason, it is necessary to finely adjust the degree of opening of the material discharge port, but such a product requires time for one-batch weighing, resulting in poor efficiency.

As means for solving these problems, there is powder supply amount adjusting means for sequentially adjusting in three stages shown in the following patent document. In this method, in order to increase the weighing accuracy, the supply amount is stepped into large, medium, and small, and when this medium weighing time is measured and becomes longer than the preset value, the large weighing time in the previous step is measured. When the medium measurement time is shortened and the medium measurement time is shortened, the large measurement time is shortened so that the medium measurement time is adjusted to a predetermined time.
Japanese Examined Patent Publication No. 6-12288

  However, in this method, it is necessary to set the intermediate measurement time in advance. If the material and measurement value are different, the measurement accuracy and measurement time associated with the material change will not be satisfied unless the appropriate time is set appropriately. . If the material is replaced with a material with an extremely different density, the possibility of over weighing increases. Also, the weighing time becomes longer.

  In consideration of shortening the weighing time, it is difficult to set the weighing time in the shortest time if it is necessary to set the weighing time in advance. If the measurement time is not obtained as a result of the identification of the material and the device, if the characteristic value of the material is different, it will be overscaled and may cause a fatal defect as a measuring instrument.

  The present invention has been proposed in view of the above circumstances, and an object of the present invention is to provide a one-batch weighing method for granular materials that can accurately measure granular materials in a short time. is there.

In order to achieve the above object, the method for measuring a granular material according to the first aspect of the present invention according to claim 1 uses a final measurement set value in one batch measurement and a final measurement set value based on a head value. A pre-measurement setting process that prepares at least a plurality of intermediate cumulative weighing values and tolerances to reach the point, and pauses until the final intermediate cumulative weighing value is reached from the first intermediate cumulative weighing value in a step-down metering step the supply amount stepwise reduced by supplying a powdered or granular material in the measuring instrument provided with a load cell to perform the metering, after the step-down metering process, than the final metering setpoint until reaching the fall value amount corresponding small final adjustment metric, and final adjustment metering performing a weighed further reduce the supply amount of the powdered or granular material, after the final adjustment metering process, the actually measured actual fall value Calculate Referring to the measured drop value calculation process, the final weighing setting value and the allowable error, the measured 1 batch weighing value is valid if it is within the allowable error range, but is invalid if it is not within the allowable error range. And the head value is updated to a value obtained by moving and averaging the actually measured head value measured in a plurality of batch weighings determined to be valid in the evaluation judgment step. It is characterized by being set .

According to the second method of the present invention proposed in order to achieve the same object, the final measurement set value in one batch measurement and the final measurement set value are reached with reference to the head value. Before the measurement , the intermediate cumulative measurement value that becomes the passing point and the permissible error are prepared at least before the measurement setting process, and the supply amount of the granular material supplied to the measuring device provided with the load cell is continuously stopped. and it is gradually decreased, and the step-down metering performing a metered to reach the intermediate cumulative metrics, until after this step-down metering process, reaches only a small final adjustment weighing the fall value content than the final metering setpoint a final adjustment metering performing a metered by decreasing the supply amount of the powdered or granular material Moreover, after the final adjustment metering process, the measured drop value calculation step of calculating the actually measured actual fall value, above With reference to final metric set value and the allowable error, execution actually measured batch weighing result, while effective if it is within range of the allowable error, the evaluation determination step for disabling if not within the range In addition, the head value is updated and set to a value obtained by moving and averaging the actually measured head value measured in a plurality of batch weighings determined to be valid in the evaluation determining step. .

The third aspect of the present invention is characterized in that the granular material is freely dropped and supplied to a measuring instrument by controlling the degree of opening of the material discharge port of the hopper storing the granular material.

According to claim 4, the supply amount of the dispensing means and attached to a hopper which stores the powdered or granular material by variably controlling, and supplying the granular material into the meter.

According to a fifth aspect of the present invention, the intermediate cumulative metric value is set as an integer multiple of the drop value .

  According to the first method of the present invention, in the step-down weighing process, the material supply is started at a large supply amount at first, and the supply amount is paused step by step every time the preset intermediate cumulative measurement value is reached. Because it is weighed with pinching, quick and accurate batch measurement can be performed. In the final adjustment weighing process, since the material supply is further reduced before weighing, the weighing accuracy is good and the error due to the drop amount can be reduced.

  In the first aspect of the present invention, as a material supply means from the hopper to the measuring instrument, a material cutting device such as a screw feeder as well as a slide damper, a gate damper, a flap damper and the like using free fall can be applied. . In addition, when supplying the material by free fall, it is desirable that the damper provided at the material discharge port of the hopper is provided with a biting prevention function, but it is easy to control because it has normal response.

According to the second method of the present invention, in the step-down metering process, the material supply is started at a large supply amount at first, and the supply amount is gradually decreased without stopping until the intermediate cumulative measurement value is reached. Therefore, one batch can be measured quickly and accurately. Further, in the final adjustment weighing process, since the material supply is further reduced before weighing, the accuracy is high and the error due to the drop amount can be reduced.

  In the second aspect of the present invention, as a material supply means from the hopper to the measuring instrument, a material cutting device such as a screw feeder can be applied in addition to a slide damper, a gate damper, a flap damper, etc. using free fall. . In addition, when the material is supplied in a free fall, it is desirable that the damper provided at the material discharge port of the hopper has a high follow-up property that can control the opening degree steplessly even without the biting prevention function.

  According to the metering method of the third aspect, the degree of opening of the material discharge port is controlled to be reduced and sequentially reduced, so that the metering can be performed by a free fall with a stable supply amount.

  According to the measuring method of the fourth aspect, since the quantitative supply means is attached to the hopper, the material can be supplied with a constant supply amount, and more accurate measurement can be performed.

In addition, according to the first method of the present invention and the second method of the present invention, the head value set in the pre-measurement setting step is obtained by the moving average of the head amount actually measured in the batch weighing so far. Therefore, an accurate predicted value can be obtained, and as a result, weighing with less error can be performed.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a conceptual diagram showing a method for measuring a granular material according to the present invention. Here, although the hopper 10 shows what provided the slide shutter in the material discharge port, the structure which provided the gate damper and the flap damper may be sufficient.

  In FIG. 1, 10 is a hopper that stores the granular material P, 11 is a slide shutter provided at a material discharge port of the hopper 10, 12 is a servo cylinder for controlling the opening of the material discharge port, and 1 is a load cell 2. It is a measuring instrument.

  In both the first and second aspects of the present invention, the first and second aspects of the present invention take in the measurement information and parameters prepared or set in advance in the pre-measurement process, and then operate a sequencer or the like to perform a step-down measurement process. The final adjustment weighing process is sequentially performed. In addition, after the final adjustment weighing process, an evaluation determination process as described later is executed.

  1 (a) and 1 (b) show a step-down weighing process, and after the material is initially charged with a large supply amount, the supply amount is stepped every time a preset intermediate cumulative measurement value is reached. Will be reduced and measured. FIG. 1 (c) shows a final adjustment weighing process executed after the step-down weighing process. In this process, a measurement value that takes into consideration a head amount generated at the end of the final adjustment weighing process is used as the final adjustment measurement value. After the weighing is performed and finally the slide shutter is closed and the weighing is finished, the head weighing as shown in FIG. 1 (d) is added and the weighing of one batch is finished.

  In this way, when one batch of measurement is completed, the load cell refers to the final measurement set value, allowable error, and drop value set in the pre-measurement setting process, and the actually measured value is within the error allowable range. It is determined whether the measured value is valid or invalid, and if it is invalid, the measurement is performed again.

  Next, the weighing algorithm of this weighing method will be described.

  FIG. 2 is a graph showing temporal changes in the material supply amount and the measurement value when the measurement method of the present invention is applied when supplying the material by free fall. In the figure, the vertical axis indicates the actual measured value measured by the load cell 2, and the horizontal axis indicates the time after starting the material supply.

  Here, WA is a final measurement value in one batch measurement, which is a target measurement value. W1 and W2 are intermediate accumulated weighing values that are passing points until the final weighing value is reached, W3 is the final drop correction weighing value, Wo is the falling value, and W1 and W2 are set as integer multiples of the falling value Wo. Has been. W3 is a final adjustment weighing value, which is a value obtained by subtracting the drop value Wo from WA. Further, although the allowable error ΔW is omitted here, these are prepared in advance in the pre-weighing process or are input and set by an operator who uses the weighing system. Here, W1 and W2 are calculated with reference to the drop value Wo, which will be described later.

  As shown in the graph of FIG. 2, (1) until the intermediate cumulative measured value reaches W1, the shutter of the discharge port is opened wide and supplied at a relatively large supply amount. The supply is stopped, and then the opening degree of the shutter is adjusted to a preset opening degree. (2) In the next stage, (1) material is supplied until W2 is reached, and further, when W2 is reached, The material supply is temporarily stopped, and finally (3) the opening degree of the shutter is further reduced and the material is supplied until reaching W3.

  Here, W3 is defined as a value in anticipation of the drop value Wo prepared in advance in the pre-measurement process, that is, a reduced final drop correction measurement value. When this value reaches W3, the shutter is fully closed and 1 is set. Material supply for the batch is completed.

  After the material supply is completed in this way, the actual head amount Wo ′ is added to the measuring instrument 1, and then (4) the load cell 2 supplies the one batch supplied to the measuring instrument 1. Is actually measured. Thus, in the next evaluation discrimination step, the actually measured supply amount of one batch is discriminated whether it is within the allowable error range by referring to the final measurement set value and the allowable error prepared in advance. If it is, the measurement is evaluated as invalid, otherwise it is evaluated as invalid, and the measurement determined as invalid is performed again.

  In FIG. 2, the material supply in the final adjustment weighing process until reaching W2 to W3 is further smaller than the supply amount in the step-down weighing process, and the degree of increase in the intermediate cumulative measurement value is also small. The accumulated amount W is approximately represented by a straight line.

  In the example of FIG. 2, the first intermediate cumulative measurement value is set to be large, and the subsequent intermediate cumulative measurement value is set so that the increase degree of the intermediate cumulative measurement value is small. In the second half of weighing, it is easier to adjust. The intermediate cumulative measurement value in the step-down measurement process may be set in two or more stages depending on the purpose of measurement.

  FIG. 3 is a flowchart showing a method of measuring the granular material according to the present invention.

  Steps 101 to 103 are pre-measurement setting steps. That is, in order to calculate the final measurement value WA, the allowable error ΔW, the drop value Wo, and the intermediate cumulative measurement values W1 to W3, which are measurement target values, in the step of setting various setting data necessary for measurement and evaluation in advance. Parameters K1 and K2 are set.

  As these setting data, experience values or data set by the user at the time of use are applied. The allowable error ΔW and the drop value Wo are not limited to those input by the user, and experience values that are updated for each batch weighing and stored in the storage device may be used. In this example, the intermediate cumulative weighing values W1 to W2 are calculated based on the parameters K1 and K2. However, these may be set in advance by experience values or the user side.

When the parameters K1 and K2 are input, the intermediate cumulative weighing values W1, W2, and W3 are calculated by the following calculation formula.
W1 = WA-K1 * Wo
W2 = WA-K2 * Wo
W3 = WA-Wo
For example, if WA = 5000 g, Wo = 50 g, K1 = 20, K2 = 10, W1 = 5000−20 * 50 = 4000 g, W2 = 5000−10 * 50 = 4500 g, W3 = 5000−50 = 4950 g .

  Steps 104 to 112 are step-down weighing processes.

  Here, the intermediate cumulative weighing value is once changed from W1 to W2, and the supply amount is stepped down to decrease the increase amount of the cumulative amount stepwise. That is, until the cumulative measurement actual value W by the load cell reaches W1, material supply is started with the degree of opening of the discharge port corresponding to a relatively large supply amount, and when W1 is reached, the material discharge port is closed and material supply is started. Once stopped (steps 104 to 108). Next, the intermediate cumulative measurement value is changed to W2, material supply is started with an opening degree corresponding to a medium supply amount, and the supply is continued until the cumulative measurement actual value W reaches W2, When W2 is reached, the material supply is temporarily stopped (steps 109 to 112).

  In this example, the step-down is performed once, but the step-down may be performed a plurality of times. In that case, it goes without saying that further parameters Kn.

  Steps 113 to 116 are final adjustment weighing processes. The intermediate cumulative measurement value is changed to W3 and material supply is started with an opening degree corresponding to the small-capacity initial speed supply amount. Until the cumulative measurement actual value W reaches W3, the replenishment is continued and reaches W3. Then, the material supply is stopped (steps 113 to 116).

  In step 117, the drop difference after the material supply in the final adjustment weighing process is stopped is actually measured.

  Steps 118 to 121 are evaluation discriminating steps for evaluating the results measured by the above steps. That is, if the measured measurement value is within the range of the allowable error ΔW, the measured one batch measurement value is validated. Otherwise, the one batch measurement value is invalidated. When it is valid, the head value Wo used in the next measurement is updated with the actually measured head value.

  For the drop value Wo to be updated, for example, a moving average value of the past n times of measured drop values in the measurement under the same condition is adopted. Further, in consideration of the secular change of the hopper 10 and its material discharge port 11, it may be calculated by a moving average value calculation formula in which the ratio of the latest actually measured drop value is increased.

  Applying WA = 5000g, Wo = 50g, K1 = 20, K2 = 10 to the above weighing method results in W1 = 5000-20 * 50 = 4000g, so it is large until the actual measured weight W reaches 4000g. Although the capacity is supplied, the material supply is temporarily stopped when W1 is reached, and then the medium capacity supply is performed. In addition, since W2 = 5000−10 * 50 = 4500 g, medium capacity supply is made when the actually measured weight value W is 4000 g to 4500 g, but when the measured weight value exceeds 4500 g, final adjustment weighing is started, and small capacity supply is started. When it becomes = 5000-50 = 4950g, material supply stops and a fall difference falls naturally.

  As described above, a large part of the material (4500 g out of 5000 g in the above example) is supplied step by step with the supply amount of large capacity and medium capacity, and the remaining adjustment part (4950-4500 = 450 g in the above example) Can be metered at high speed and accurately. Particularly in the final adjustment stage, since the material can be supplied with a small supply amount, the amount of the drop difference can be reduced.

  Further, since the setting of the intermediate cumulative weighing value is set by a multiple of the head value, if the head value to be set is close to the actual measurement value, highly accurate weighing can be expected. In particular, since the head value to be set is calculated by moving average of past actual measurement values, precise predicted values can be obtained and accurate weighing can be realized.

  Further, since there is no need for dynamic control that narrows the material discharge port 11 as the material supply progresses, the control is extremely easy, and if a damper or the like having a biting prevention function is used, the material There is no concern about material biting when the discharge port 11 is closed in stages.

  In the above embodiment, the material discharge port 11 is of a slide shutter type, and the material discharge port 11 is opened and closed with an opening degree corresponding to the supply amount in order to set and control the (initial speed) supply amount of the material P stepwise. Although shown, the throttle control may be performed so that the material discharge port 11 is gradually reduced so that the metered supply of the granular material P is gradually reduced, and the quantitative supply means such as a screw feeder capable of variably controlling the supply amount May be attached to the hopper 10. According to these, materials can be supplied by free fall with a constant supply amount, and more accurate weighing can be performed.

  Further, the supply amount of the granular material P is increased by other methods without controlling the opening of the material discharge port 11 until the intermediate cumulative measured value of the first stage is reached, and thereafter the final intermediate cumulative measured value is reached. The metering of the granular material P may be controlled to gradually decrease until the value is reached.

  FIG. 4 is a graph showing temporal changes in the material supply amount and the measured value when the second measuring method of the present invention is applied when the material is supplied in free fall. In the figure, the vertical axis indicates the actual measured value measured by the load cell 2, and the horizontal axis indicates the time after starting the material supply.

  Here, WA is a final measurement value in one batch measurement, which is a target measurement value. W2 is the final intermediate accumulated metric value, W3 is the final adjusted metric value, and Wo is the drop value. Here, W2 is set as an integral multiple of the drop value Wo, W3 is a value obtained by subtracting the drop value Wo from WA, and the allowable error ΔW is omitted here. These are prepared in advance in the pre-weighing process or input and set by an operator who uses the weighing system. Here, W2 is calculated based on the drop value Wo, but an experience value or an arbitrary value set by the user may be used.

  As shown in the graph of FIG. 4, (1) until the final cumulative value W2 of the intermediate cumulative measured value is reached, the material is supplied while gradually closing the shutter of the discharge port. After that, the opening degree of the shutter is adjusted to a preset opening degree. Finally, (3) the opening degree of the shutter is further reduced and the material is supplied until W3 is reached.

  Here, as described above, W3 is defined as a value in anticipation of the drop value Wo prepared in advance in the pre-measurement process, that is, as a reduced final drop correction measurement value. The material supply is completed for one batch.

  After the material supply is completed in this way, the actual head amount Wo ′ is added to the measuring instrument 1, and then (4) the load cell 2 supplies the one batch supplied to the measuring instrument 1. Is actually measured. Thus, in the next evaluation discrimination step, the actually measured supply amount of one batch is discriminated whether it is within the allowable error range by referring to the final measurement set value and the allowable error prepared in advance. If it is, the measurement is evaluated as invalid, otherwise it is evaluated as invalid, and the measurement determined as invalid is performed again.

  FIG. 5 shows a flow chart of a method for measuring the material while gradually decreasing the supply of the granular material.

  In this method, in the pre-measurement setting step, various parameters are set in the same manner as in the first aspect of the present invention (steps 201 to 205), and in the step-down measurement step, the material is reduced to the intermediate cumulative measurement value W2 while successively reducing the supply amount. The material supply is temporarily stopped when W2 is reached, or the final measurement set value W3 is measured without stopping (steps 206 to 210). Thereafter, the drop difference is measured, and the same evaluation discrimination process as in the first aspect of the present invention is executed (steps 211 to 215).

  That is, in the evaluation discriminating step, if the measured measurement value is within the range of the allowable error ΔW, the measured one batch measurement value is validated, and the head value Wo measured with the one batch measurement value is used to While the head value Wo used for weighing is updated, otherwise, the head value Wo is not updated and the one batch weight value is invalidated (steps 214 to 217).

  Thus, in the second method of the present invention, the material supply in the step-down weighing process is continuously changed without being changed stepwise.

  In addition, according to this method, the material discharge port is gradually throttled steplessly, so the damper provided at the material discharge port does not need to consider the biting of the material on the way, but the servo motor drive type etc. As shown in FIG. Therefore, if the response operation is good, it can also be applied to a flap damper type outlet.

It is a conceptual diagram of the measuring method of the granular material of this invention, (a), (b) shows the step-down measuring process, (c) shows the final adjustment measuring process, (d) shows the head measurement. FIG. 2 is a graph showing stepwise measurement by the method for measuring granular material in the first invention. It is a flowchart which shows the procedure of the measuring method of the granular material material in 1st this invention. FIG. 5 is a graph showing stepwise measurement by the method for measuring granular material in the second invention. It is a flowchart which shows the procedure of the measuring method of the granular material material in 2nd this invention.

Explanation of symbols

1 Weighing device 2 Load cell 10 Hopper 11 Material discharge port (slide shutter)
12 Servo cylinder P Powder material

Claims (5)

A pre-measurement setting step for preparing at least a final measurement set value in one batch measurement, a plurality of intermediate cumulative measurement values that become a passing point until the final measurement set value is reached with reference to a head value, and an allowable error ; ,
The step of supplying the granular material to the measuring instrument provided with the load cell and performing the measurement by decreasing the supply amount step by step until the final intermediate cumulative measurement value is reached from the first intermediate cumulative measurement value. Down weighing process,
After this step-down metering process until a final adjustment weighing less only the fall value content than the final metering setting value, a final adjustment metering performing a weighed further reduce the supply amount of the powdered or granular material ,
After this final adjustment weighing step, an actually measured head value calculating step for calculating an actually measured head value,
With reference to the final weighing set value and the allowable error, an evaluation determining step that is valid if the actually measured one batch weighing value is within the range of the allowable error, and invalid if it is not within the range. Execute and
The above-mentioned head value is updated and set to a value obtained by moving average the above-mentioned actual head value measured by a plurality of batch weighings determined to be effective in the evaluation judgment step, Material weighing method. A pre-measurement setting step for preparing at least a final measurement set value in one batch measurement, an intermediate cumulative measurement value serving as a passing point until the final measurement set value is reached on the basis of a head value, and an allowable error ;
Continuously it is gradually decreased without halting the supply amount of supplying powder or granular material in the measuring instrument having a load cell, and step-down metering performing a metered to reach the intermediate cumulative metrics,
After this step-down metering process until a final adjustment weighing less only the fall value content than the final metering setting value, a final adjustment metering performing a weighed further reduce the supply amount of the powdered or granular material ,
After this final adjustment weighing step, an actually measured head value calculating step for calculating an actually measured head value,
With reference to the final weighing set value and the allowable error, an evaluation determining step that is valid if the actually measured one batch weighing value is within the range of the allowable error, and invalid if it is not within the range. Execute and
The above-mentioned head value is updated and set to a value obtained by moving average the above-mentioned actual head value measured by a plurality of batch weighings determined to be effective in the evaluation judgment step, Material weighing method. In claim 1 or 2,
A method for measuring granular material, wherein the granular material is freely dropped and supplied to the measuring instrument by controlling the degree of opening of the material discharge port of the hopper storing the granular material. . In claim 1 or 2,
A method for measuring a granular material, characterized in that the supply amount of a quantitative supply means attached to a hopper that stores the granular material is variably controlled, and the granular material is supplied to the measuring device. In any one of claims 1 to 4,
The method for measuring granular material, wherein the intermediate cumulative measured value is set as an integer multiple of the drop value .

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